如何在flask中将变量值从一个函数渲染到另一个函数，

from flask import Flask

app = Flask(__name__)
my_variable = None

@app.route('/')
def set_variable():
    global my_variable
    my_variable = 'Hello, Flask!'
    return 'Variable set'

@app.route('/get')
def get_variable():
    global my_variable
    return my_variable

if __name__ == '__main__':
    app.run()

from flask import Flask, session

app = Flask(__name__)
app.secret_key = 'your_secret_key'

@app.route('/')
def set_variable():
    session['my_variable'] = 'Hello, Flask!'
    return 'Variable set'

@app.route('/get')
def get_variable():
    return session.get('my_variable', 'Variable not set')

if __name__ == '__main__':
    app.run()

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///app.db'
db = SQLAlchemy(app)

class Variable(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50), unique=True)
    value = db.Column(db.String(100))

@app.route('/')
def set_variable():
    variable = Variable(name='my_variable', value='Hello, Flask!')
    db.session.add(variable)
    db.session.commit()
    return 'Variable set'

@app.route('/get')
def get_variable():
    variable = Variable.query.filter_by(name='my_variable').first()
    return variable.value if variable else 'Variable not set'

if __name__ == '__main__':
    app.run()

from flask import Flask, redirect, url_for

app = Flask(__name__)

@app.route('/')
def set_variable():
    return redirect(url_for('get_variable', my_variable='Hello, Flask!'))

@app.route('/get/<my_variable>')
def get_variable(my_variable):
    return my_variable

if __name__ == '__main__':
    app.run()